Outcomes of de novo CD5+ diffuse large b-cell lymphoma (DLBCL) in the rituximab (R) era.

Abstract

e19019 Background: De novo CD5+ DLBCL is associated with poor prognosis. Methods: We retrospectively reviewed the MD Anderson Lymphoma Outcome Database and identified 104 patients (pts) with de novo CD5+ DLBCL diagnosed between 2001-2016. We excluded primary CNS lymphoma and Richter’s transformation. Results: Median age was 62 (range 29-96); 55% were male. Most (71%) pts had advanced stage at diagnosis, with 55% being Stage IV. Eighty percent (n = 79) had extranodal disease at presentation with bone/bone marrow being the most common site (40%); central nervous involvement was seen in 5%. Two-thirds had elevated LDH; 37% had B symptoms on presentation. ECOG PS was ≥2 in 26% of pts; beta-2 microglobulin was elevated in 68%. Of the 77 pts with IPI score, 21% (n = 16), 23% (n = 18), 26% (n = 20), and 30% (n = 23) were considered low, low-intermediate, high-intermediate, and high risk, respectively. In the diagnostic specimen, median Ki67 was 85%. Majority were non-GCB by Han’s criteria (n = 47 of 77). Two pts were double-hit lymphoma. All received R-containing regimens for primary therapy, including RCHOP (n = 64), dose-adjusted R-EPOCH (n = 24), R-HyperCVAD (n = 6), and other (n = 10). Prophylactic intrathecal chemotherapy use was 35%. Sixty-eight (65%) pts achieved complete response (CR) with primary therapy. Two pts underwent frontline autologous stem cell transplant. Median PFS duration was 28 months (mo) (95% CI: 10-27). Median OS duration was 112 mo (95% CI: 10-214). Pts with primary refractory disease had the worst OS duration of 14 mo. Pts with relapse within 1 year of achieving CR fared no better with median OS of 22 mo. PFS and OS were not significantly different by choice of primary therapy. By multivariate analysis using Cox proportional hazard model, male gender (HR = 3.0, 95% CI: 1.1-8.1, p = 0.029) and high IPI (HR = 2.5, 95% CI: 1.4-4.3, p = 0.001) were associated with shorter PFS. Only IPI score was significantly associated with worse OS (HR = 3.0, 95% CI: 1.6-5.7, p = 0.001). Conclusions: De novo CD5+ DLBCL is frequently associated with extranodal presentation and poor outcome with R-containing intensive chemotherapy. IPI remains the most significant prognostic factor for worse PFS and OS. There is clearly an unmet need for novel treatment for this disease.